package org.feezu.liuli.timeselector.view;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.Align;
import android.graphics.Paint.FontMetricsInt;
import android.graphics.Paint.Style;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

import org.feezu.liuli.timeselector.R;

import java.util.ArrayList;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask;


public class PickerView extends View
{
	/**
	 * 新增字段 控制是否首尾相接循环显示 默认为循环显示
	 */
	private boolean loop = true;
	
	/**
	 * text之间间距和minTextSize之比
	 */
	public static final float MARGIN_ALPHA = 2.8f;

	/**
	 * 自动回滚到中间的速度
	 */
	public static final float SPEED = 10;

	private List<String> mDataList;

	/**
	 * 选中的位置，这个位置是mDataList的中心位置，一直不变
	 */
	private int mCurrentSelected;

	private Paint mPaint, nPaint;

	private float mMaxTextSize = 80;

	private float mMinTextSize = 40;

	private float mMaxTextAlpha = 255;

	private float mMinTextAlpha = 120;

	private int mColorText = 0x333333;

	private int nColorText = 0x666666;

	private int mViewHeight;

	private int mViewWidth;

	private float mLastDownY;

	/**
	 * 滑动的距离
	 */
	private float mMoveLen = 0;

	private boolean isInit = false;

	private onSelectListener mSelectListener;

	private Timer timer;

	private MyTimerTask mTask;

	Handler updateHandler = new Handler()
	{

		@Override
		public void handleMessage(Message msg)
		{
			if (Math.abs(mMoveLen) < SPEED)
			{
				mMoveLen = 0;
				if (mTask != null)
				{
					mTask.cancel();
					mTask = null;
					performSelect();
				}
			}
			else
			// 这里mMoveLen / Math.abs(mMoveLen)是为了保有mMoveLen的正负号，以实现上滚或下滚
			{
				mMoveLen = mMoveLen - mMoveLen / Math.abs(mMoveLen) * SPEED;
			}
			invalidate();
		}

	};

	private boolean canScroll = true;

	public PickerView(Context context)
	{
		super(context);
		init();
	}

	public PickerView(Context context, AttributeSet attrs)
	{
		super(context, attrs);
		TypedArray typedArray = getContext().obtainStyledAttributes(attrs, R.styleable.PickerView);
		loop = typedArray.getBoolean(R.styleable.PickerView_isLoop, loop);
		init();
	}

	public void setOnSelectListener(onSelectListener listener)
	{
		mSelectListener = listener;
	}

	private void performSelect()
	{
		if (mSelectListener != null)
		{
			mSelectListener.onSelect(mDataList.get(mCurrentSelected));
		}
	}

	public void setData(List<String> datas)
	{
		mDataList = datas;
		mCurrentSelected = datas.size() / 4;
		invalidate();
	}

	/**
	 * 选择选中的item的index
	 *
	 * @param selected
	 */
	public void setSelected(int selected)
	{
		mCurrentSelected = selected;
		if (loop)
		{
			int distance = mDataList.size() / 2 - mCurrentSelected;
			if (distance < 0)
			{
				for (int i = 0; i < -distance; i++)
				{
					moveHeadToTail();
					mCurrentSelected--;
				}
			}
			else if (distance > 0)
			{
				for (int i = 0; i < distance; i++)
				{
					moveTailToHead();
					mCurrentSelected++;
				}
			}
		}
		invalidate();
	}

	/**
	 * 选择选中的内容
	 *
	 * @param mSelectItem
	 */
	public void setSelected(String mSelectItem)
	{
		for (int i = 0; i < mDataList.size(); i++)
		{
			if (mDataList.get(i).equals(mSelectItem))
			{
				setSelected(i);
				break;
			}
		}
	}


	private void moveHeadToTail()
	{
		if (loop)
		{
			String head = mDataList.get(0);
			mDataList.remove(0);
			mDataList.add(head);
		}
	}

	private void moveTailToHead()
	{
		if (loop)
		{
			String tail = mDataList.get(mDataList.size() - 1);
			mDataList.remove(mDataList.size() - 1);
			mDataList.add(0, tail);
		}

	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
	{
		super.onMeasure(widthMeasureSpec, heightMeasureSpec);
		mViewHeight = getMeasuredHeight();
		mViewWidth = getMeasuredWidth();
		// 按照View的高度计算字体大小
		mMaxTextSize = mViewHeight / 7f;
		mMinTextSize = mMaxTextSize / 2.2f;
		isInit = true;
		invalidate();
	}

	private void init()
	{
		timer = new Timer();
		mDataList = new ArrayList<String>();
		//第一个paint
		mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
		mPaint.setStyle(Style.FILL);
		mPaint.setTextAlign(Align.CENTER);
		mPaint.setColor(getResources().getColor(android.R.color.holo_orange_dark));
		//第二个paint
		nPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
		nPaint.setStyle(Style.FILL);
		nPaint.setTextAlign(Align.CENTER);
		nPaint.setColor(mColorText);
	}

	@Override
	protected void onDraw(Canvas canvas)
	{
		super.onDraw(canvas);
		// 根据index绘制view
		if (isInit)
		{
			drawData(canvas);
		}
	}

	private void drawData(Canvas canvas)
	{
		// 先绘制选中的text再往上往下绘制其余的text
		float scale = parabola(mViewHeight / 4.0f, mMoveLen);
		float size = (mMaxTextSize - mMinTextSize) * scale + mMinTextSize;
		mPaint.setTextSize(size);
		mPaint.setAlpha((int) ((mMaxTextAlpha - mMinTextAlpha) * scale + mMinTextAlpha));
		// text居中绘制，注意baseline的计算才能达到居中，y值是text中心坐标
		float x = (float) (mViewWidth / 2.0);
		float y = (float) (mViewHeight / 2.0 + mMoveLen);
		FontMetricsInt fmi = mPaint.getFontMetricsInt();
		float baseline = (float) (y - (fmi.bottom / 2.0 + fmi.top / 2.0));

		canvas.drawText(mDataList.get(mCurrentSelected), x, baseline, mPaint);
		// 绘制上方data
		for (int i = 1; (mCurrentSelected - i) >= 0; i++)
		{
			drawOtherText(canvas, i, -1);
		}
		// 绘制下方data
		for (int i = 1; (mCurrentSelected + i) < mDataList.size(); i++)
		{
			drawOtherText(canvas, i, 1);
		}

	}

	/**
	 * @param canvas
	 * @param position 距离mCurrentSelected的差值
	 * @param type     1表示向下绘制，-1表示向上绘制
	 */
	private void drawOtherText(Canvas canvas, int position, int type)
	{
		float d = (float) (MARGIN_ALPHA * mMinTextSize * position + type
				* mMoveLen);
		float scale = parabola(mViewHeight / 4.0f, d);
		float size = (mMaxTextSize - mMinTextSize) * scale + mMinTextSize;
		nPaint.setTextSize(size);
		nPaint.setAlpha((int) ((mMaxTextAlpha - mMinTextAlpha) * scale + mMinTextAlpha));
		float y = (float) (mViewHeight / 2.0 + type * d);
		FontMetricsInt fmi = nPaint.getFontMetricsInt();
		float baseline = (float) (y - (fmi.bottom / 2.0 + fmi.top / 2.0));
		canvas.drawText(mDataList.get(mCurrentSelected + type * position),
				(float) (mViewWidth / 2.0), baseline, nPaint);
	}

	/**
	 * 抛物线
	 *
	 * @param zero 零点坐标
	 * @param x    偏移量
	 * @return scale
	 */
	private float parabola(float zero, float x)
	{
		float f = (float) (1 - Math.pow(x / zero, 2));
		return f < 0 ? 0 : f;
	}

	@Override
	public boolean onTouchEvent(MotionEvent event)
	{
		switch (event.getActionMasked())
		{
			case MotionEvent.ACTION_DOWN:
				doDown(event);
				break;
			case MotionEvent.ACTION_MOVE:
				mMoveLen += (event.getY() - mLastDownY);

				if (mMoveLen > MARGIN_ALPHA * mMinTextSize / 2)
				{
					if (!loop && mCurrentSelected == 0)
					{
						mLastDownY = event.getY();
						invalidate();
						return true;
					}
					if (!loop)
					{
						mCurrentSelected--;
					}
					// 往下滑超过离开距离
					moveTailToHead();
					mMoveLen = mMoveLen - MARGIN_ALPHA * mMinTextSize;
				}
				else if (mMoveLen < -MARGIN_ALPHA * mMinTextSize / 2)
				{
					if (mCurrentSelected == mDataList.size() - 1)
					{
						mLastDownY = event.getY();
						invalidate();
						return true;
					}
					if (!loop)
					{
						mCurrentSelected++;
					}
					// 往上滑超过离开距离
					moveHeadToTail();
					mMoveLen = mMoveLen + MARGIN_ALPHA * mMinTextSize;
				}

				mLastDownY = event.getY();
				invalidate();
				break;
			case MotionEvent.ACTION_UP:
				doUp(event);
				break;
		}
		return true;
	}

	private void doDown(MotionEvent event)
	{
		if (mTask != null)
		{
			mTask.cancel();
			mTask = null;
		}
		mLastDownY = event.getY();
	}

	//    private void doMove(MotionEvent event) {
	//
	//        mMoveLen += (event.getY() - mLastDownY);
	//
	//        if (mMoveLen > MARGIN_ALPHA * mMinTextSize / 2) {
	//            // 往下滑超过离开距离
	//            moveTailToHead();
	//            mMoveLen = mMoveLen - MARGIN_ALPHA * mMinTextSize;
	//        } else if (mMoveLen < -MARGIN_ALPHA * mMinTextSize / 2) {
	//            // 往上滑超过离开距离
	//            moveHeadToTail();
	//            mMoveLen = mMoveLen + MARGIN_ALPHA * mMinTextSize;
	//        }
	//
	//        mLastDownY = event.getY();
	//        invalidate();
	//    }

	private void doUp(MotionEvent event)
	{
		// 抬起手后mCurrentSelected的位置由当前位置move到中间选中位置
		if (Math.abs(mMoveLen) < 0.0001)
		{
			mMoveLen = 0;
			return;
		}
		if (mTask != null)
		{
			mTask.cancel();
			mTask = null;
		}
		mTask = new MyTimerTask(updateHandler);
		timer.schedule(mTask, 0, 10);
	}

	class MyTimerTask extends TimerTask
	{
		Handler handler;

		public MyTimerTask(Handler handler)
		{
			this.handler = handler;
		}

		@Override
		public void run()
		{
			handler.sendMessage(handler.obtainMessage());
		}

	}

	public interface onSelectListener
	{
		void onSelect(String text);
	}

	public void setCanScroll(boolean canScroll)
	{
		this.canScroll = canScroll;
	}

	@Override
	public boolean dispatchTouchEvent(MotionEvent event)
	{
		if (canScroll)
		{
			return super.dispatchTouchEvent(event);
		}
		else
		{
			return false;
		}
	}

	/**
	 * 新增字段 控制内容是否首尾相连
	 * by liuli
	 *
	 * @param isLoop
	 */
	public void setIsLoop(boolean isLoop)
	{
		loop = isLoop;
	}
}